Apparatus and method monitoring semiconductor manufacturing equipment

Abstract

An apparatus monitoring semiconductor manufacturing equipment includes an optical detector, a light generator generating light along an optical path towards a semiconductor substrate, a first grating reticle between the light generator and the semiconductor substrate and including first slits having a first pitch and second slits having a second pitch different from the first pitch, a second grating reticle between the semiconductor substrate and the optical detector and including third slits having a third pitch different from the first pitch and the second pitch, in which the optical detector determines a positional attribute of the semiconductor substrate in relation to a first pattern and a second pattern, the first pattern corresponds to a first portion of light sequentially passing through the first slits and the third slits, and the second pattern corresponds to a second portion of light sequentially passing through the second slits and the third slits.